The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 24, 2011
Filed:
Oct. 20, 2005
Mingkwang Han, Singapore, SG;
Footshen Wong, Singapore, SG;
Vlad Popescu-stanesti, San Jose, CA (US);
Winson Wong, Singapore, SG;
Jacky Lin, Yi-Lan Shien, TW;
Mingkwang Han, Singapore, SG;
Footshen Wong, Singapore, SG;
Vlad Popescu-Stanesti, San Jose, CA (US);
Winson Wong, Singapore, SG;
Jacky Lin, Yi-Lan Shien, TW;
02Micro Inc., Santa Clara, CA (US);
Abstract
The present invention is an apparatus for driving white LEDs. The apparatus includes a switchable current sink, a DC-DC converter and a reference circuit. The DC-DC converter provides a driving voltage to a plurality of LEDs. The switchable current sink regulates currents through the plurality of LEDs, and the switchable current sink further provides a first reference voltage and outputs a plurality of voltage drops. The reference circuit receives the first reference voltage and the plurality of voltage drops to provide a second reference voltage to the DC-DC converter. The DC-DC converter adjusts the driving voltage provided to the plurality of LEDs according to the second reference voltage. In this way, the driving voltage is regulated to a minimum possible value and consequently the voltage drops across the switchable current sink is minimized. Hence, the LED driving system maintains higher efficiency.